Yarn quality assessment method and apparatus therefor

ABSTRACT

A method and apparatus for assessing knitting quality of yarn which comprises a plurality of elements which operatively cooperate so that some prediction can be made about the knitting quality of the yarn by the detection of the accumulated value of the resistances to various forces as a yarn winding tension, and by the comparison of the data with the respective standard value, an evaluation of the yarn can be made easily and simply before the yarn is knitted.

United States Patent [191 Sasaki et a1.

[451 Aug. 27, 1974 YARN QUALITY ASSESSMENT METHOD AND APPARATUS THEREFORInventors: Toshiro Sasaki, Osaka; Katsuaki Kuroda, Kyoto, both of JapanKurashiki Boseki Kabushiki Kaisha (a/k/a Kurabo Industries Ltd.),Kurashiki-shi, Okayama-ken, Japan Filed: Jan, 26, 1973 Appl. No.:326,695

Assignee:

Foreigi Application Priority Data Jan. 26, 1972 Japan 47-10153 June 16,1972 Japan 47-60660 US. Cl. 73/160, 73/9 Int. Cl. G011 5/06 Field ofSearch 73/160, 9, 95.5

References Cited UNITED STATES PATENTS 10/1965 Schlatter 73/1603,726,137 4/1973 Demon 73/160 FOREIGN PATENTS OR APPLICATIONS 842,9197/1960 Great Britain 73/9 Primary Examiner-Richard C. Queisser AssistantExaminerDenis E. Corr Attorney, Agent, or Firm-Wenderoth, Lind & Ponack[57] ABSTRACT 9 Claims, 10 Drawing Figures YARN QUALITY ASSESSMENTMETHOD AND APPARATUS THEREFOR The present invention relates to a methodand apparatus for determining the quality of yarn or the like used inthe production of natural and/or synthetic fabrics. More particularlythe invention relates to a method and apparatus whereby the quality of ayarn, etc., as based on the results of a plurality of normal industrialtests, such as unwinding, needle-to-yarn, yarnto-yarn frictionalresistance tests, can be determined in one single operation.

As is well known, in textile fabric production use is made of yarns orthreads which have a variety of characteristics, and which are subjectedto a variety of preliminary processes, such as mercerising, waxing,etc., and there is also a considerable variety of composition of yarns,which may be, for example, 100 percent cotton, or varying blends ofcotton or other materials. Tensile stresses and other forces that yarnsare able to bear obviously vary from yarn to yarn according tocomposition and preliminary treatment, and may also vary from yarns thathave the same composition and have received the same preliminarytreatment. A constant problem, therefore, in industry, is to determinethe quality of a yarn that is to be used, for example, in a knittingmill, in order to avoid stoppages due -to breakage, etc., and to ensureexcellent quality and smooth operation on a mass-production basis. Byquality is meant the knittablity of yarns, that is the stresses they canwithstand and the ease or difficulty withwhich they can be knitted orwoven. This assessment of yarn quality is made on the basis of a numberof criteria and yarns are generally classified as good (i.e., they knitsmoothly and produce finished goods without flaws), medium (i.e.,knitting operation can proceed but is usually attended by somedifficulty and requires fairly constant adjustments to be made inorderto produce finished goods), or poor (i.e., either that knitting isimpossible, or even if it is possible, the finished goods produced areunsaleable). The reason why a number of different criteria for assessingyarn quality is necessary, is that in practical operation, in passingthrough a knitting machine, yarn is subject to not one but a number ofdifferent tensile forces and resistances. These forces and resistancesgenerally include;

1. Unwinding resistance (produced when a yarn is unwound from a cheese,or cone, etc.)

2. Yarn-to-yarn frictional force (also termed crossover resistance orfriction, and meaning the mutual frictional resistance offered betweentwo lengths of one and the same yarn at a point where the yarn iscrossed on itself) 3. Needle-to-yarn frictional force (i.e., frictionalresistance between a yarn and a needle through which it is threaded) 4.Yarn bending moment (i.e., the force imposed on a yarn by bending itsharply once or repeatedly) 5. Yarn tensile strength and elongation atthe breaking point 6. Youngs Modulus of initial tension 7. Yarnunevenness (U%).

As far as a particular yarn is concerned, more than one of theseresistances and forces is present, but since they are imposed at variouspoints over the length of the same be represented conventionally as onesingle force, and assessment of yarn quality requires the attention ofskilled operators to carry out various tests to determine a yarnsqualities with respect to individual resistances, and forces, and thencombine the results of tests in a manner previously determined on thebasis of experience, in order to classify the yarn as good, medium. orpoor. The various factors to be considered and their differentcorrelations for different yarns make assessment of yarn quality in thismanner exceedingly complex, and because the assessment is so dependenton the accuracy of individual tests, the testing must be entrusted toskilled workmen, and even if test results are accurate, assessment isrendered difficult because of the fact that what may be a satisfactoryvalue of, for example, needle-to-yarn frictional resistance for a yarnin one situation may not be satisfactory for another yarn, or for thesame yarn in another situation. Such a procedure therefore, is obviouslytime-consuming, and expensive, since it requires skilled operators and avariety of equipment, and also, the mere fact that there are a pluralityof tests increases the possibility of error, and the procedure is farfrom ideal for a mass-production industry such as textile manufacturing.

It is an-object, therefore, of this invention to provide a method andapparatus wherein. a yarn to be tested is unwound from a cheese or cone,passed through a unit where cross-over friction, yarn to needlefriction, and bending resistance are generated, and then wound up againat a constant speed by a take-up reel, and the total resistive forcerepresenting the above-mentioned cross-over friction, yarn-to-needlefriction and bending resistance, is measured at the take-up point andthe measured value is compared with standard values obtained when-yarnsof known qualities in the same manner, thus making it possible, by asimple and single operation, to classify a yarn into one of threeclasses, that are good, medium, or poor.

Another object of the invention is to provide a yarn quality assessmentmethod and apparatus wherein a yarn or similar material to be tested isunwound from a cheese or cone, passed through a means for generatingunwinding resistance, through a means for generating cross-over (i.e.,yarn to yarn) frictional resistance, yarn to needle frictionalresistance, and bending resistance and then wound up again at a constantspeed by a take-up means and wherein there is provided a detection meansfor mesuring a tensile force which represents the accumulative value ofat least one or more of the above-mentioned resistances. The detectionmeans consists essentially of a floating pulley which is subject to anupwardly acting force provided by the said accumulative tensile forceand to which is attached a set weight, it being observed to whatposition the floating pulley moves relative to a previously determinedset level.

A further object of the invention is to provide a yarn qualityassessment method and apparatus which comprise a floating pulley for thepurpose of measuring an accumulative tensile force on a tested yarn, asdescribed above, and which further comprise a means for continuouslyvarying the weight acting downwards on the floating pulley, said meansessentially comprising a freely suspended chain the position of one endof which can be adjusted in such a manner as to change the fraction ofthe weight of the chain that is imposed on the floating pulley, thusmaking it possible to assess yarn quality over a continuous range; inother words by a single, simple apparatus and method the invention makesit possible not only to classify yarns broadly into three classes, good,medium, poor, but also to assess yarns much more closely by observationof the movement of a floating pulley.

These and other features and objects of the present invention willbecome apparent from the following full description taken in conjunctionwith preferred embodiments thereof and with reference to the attacheddrawings, in which;

FIG. 1 is a perspective view of one preferred embodiment of a yarnquality assessment apparatus according to the invention,

FIG. 2 is a perspective view, on an enlarged scale, of a movable guidepulley employed in the apparatus of FIG. 1,

FIG. 3 is a perspective view, on an enlarged scale, of a needle holderemployed in the apparatus of FIG. 1,

FIG. 4 is a perspective view, on an enlarged scale, of a floating pulleyemployed in the apparatus of FIG. 1,

FIG. 5, (a) and (b), is a graph showing the position of the floatingpulley varying due to the influence of the accumulated resistancesapplied to a yarn,

FIG. 6 is a schematic diagram showing essential portions of anotherembodiment of a yarn quality assessment apparatus according to thepresent invention,

FIG. 7, (a) and (b), is a partially schematic diagram similar to FIG. 6for illustrating an alternative method of passing a yarn throughneedles, and

FIG. 8 is a partially schematic diagram showing an essential portion ofa further embodiment of a yarn quality assessment apparatus according tothe present invention.

Before the description of the present invention proceeds, it is to benoted that like parts are, for the sake of brevity, designated by thelike reference numerals throughout the several views of the accompanyingdrawings.

Referring first to FIGS. 1 to 4, the equipment has a flat base 1. On thebase 1 there is mounted a vertical panel 2, and adjacent to one side ofthe panel 2 there is an upright stand 3, which constitutes a support fora cone 4 of yarn, wool, silk or other material it is desired to test(hereinbelow abbreviated to yarn). The initial point of feed-in of yarnto be tested from the cone 4 to the equipment of the panel 2 (describedin further detail below) is a guide pulley 7; yarn unwound from the cone4 is led to this initial guide pulley 7 by means of a unwinding guidearm 5 on which is mounted a lead-in pulley 6. On one end 5a of the guidearm 5 there is mounted a pivot pin 50, which is slidably fitted into aguide groove Zn on the back, near the top and parallel to the upper edgeof the panel 2. The guide arm 5 extends upwards and outwards withrespect to the panel 2 (as seen from the front, obliquely upwards to theleft), and the above-mentioned pulley 6 is mounted at the outer end 5bof the guide arm 5. The guide arm 5 is free to move laterally in eitherdirection, since the pivot pin 50 is slidably fitted in the panel guidegroove 2a, and also the pivot pin 5c permits adjustment of the angle atwhich the guide arm 5 projects from the panel 2; the range of thisadjustment is such that the height of the arm end 512, and hence thepulley 6, above the base 1 can be varied by any amount up to about 100cm. Yarn from the cone 4 on the stand 3 is unwoumd,- led upwards, passedover the pulley 6, and thence led downwards and onto the guide pulley 7;in this manner, unwinding resistance of yarn fed to the guide pulley 7is generated at the pulley 6. It is preferable to set the height of thepulley 6 to within about 20 cm above the imaginary apex of the yarncone; by setting the pulley 6 to various'heights it is also possible todetermine the optimum height for positioning an unwinding guide in anactual knitting machine. The shape of the cone changes knittingqualities, of course, for the same yarn, and if it is desired todisregard unwinding resistance and assess knitting qualities from otheryarn characteristics only, this can be achieved by interposing a yarntensioner feed device or magneto tensor between the cone 4 and pulley 6.

There are six guide pulleys mounted on the front of the panel 2 and allare level with one another along a line that is in the upper portion andparallel to the top of the panel 2. From left to right (that is in thedirection of yarn travel) the pulleys are the above-mentioned firstguide pulley 7, a second guide pulley 8, a third guide pulley 9, afourth guide pulley 10, a fifth guide pulley l1, and a sixth guidepulley 12. The pulleys 8 and 9 are movable pulleys; which, respectively,are attached to brackets 8d and 9d, which are dependent from verticalsupport shafts 8a and 9a; the support shafts 8a and 9a are themselvessupported by bearings 8b and 9b connected to the panel 2; the shafts 8aand 9a are provided with cam plates 8c and which, by engagement with camportions formed in the bearings 8b and 9b, permit the pulleys 8 and 9 tobe turned through For either pulley 8 or pulley 9, if a yarn is firstpassed over the pulley and then the pulley is turned once, clockwise asseen from above, the yarn crosses itself, and thus turning the pulleyproduces the crossover friction of a yarn, that is the frictiongenerated between one length and another of the same yarn.

Since all the pulleys 6, 7, 8, 9, 10, 11 and 12 are part of an equipmentfor testing yarn qualities, it is obviously desirable that they reactaccurately to yarn tensions, etc., and be uninfluenced by externalfactors, and to this end, in the present embodiment, all the pulleys areprovided with hearings to keep rotational friction to a minimum. Ofcourse, if resistance increases uniformly in all pulleys, calculationsare not affected, and it is also possible to use open type bearings.However, from the point of view of pulley service, economy and similarconsiderations, sealed grease bearings are preferable. Also, if it ismore convenient, the pulleys 6 and 7 can be simple guide pulleys, sincevery little tension is imposed on yarn between these points, and thepulleys may even be non-rotating.

Fixed to the front of the panel 2, on a level with one another and on aline that is below and parallel to the line of the above-mentioned guidepulleys, there are three needle holders, 13, l5 and 17. The positions ofthe holders l3, l5 and 17 lie, respectively, between the first guidepulley 7 and second guide pulley 8, between the second guide pulley 8and third guide pulley 9, and between the third guide pulley 9 andfourth guide pulley 10. Each holder comprises a fixed plate (130, 15a,17a), and a movable plate (13b, 15b, 17b) attached thereto, betweenwhich a needle is held, the needles held by the holders 13, 15 and 17being respectively a first needle 14, a second needle 16, and a thirdneedle 18. The needles 14, 16 and 18 therefore lie on a line that isbelow and parallel to the line on which lie the pulleys 7, 8, 9, 10, 11and 12. Yarn unwound from the cone 4 is passed over the lead-in pulley6, passed onto the first guide pulley 7, threaded through the firstneedle 14, passed over the movable second guide pulley 8, threadedthrough the second needle 16, passed over the movable third guide pulley9, threaded through the third needle 18, and passed on to the fourthguide pulley 11; the subsequent path of the yarn will be describedlater. There is resistance generated at various points on the path ofthe yarn thus passed over pulleys and threaded on needles. Theseresistances are: unwinding resistance at the lead-in pulley 6,frictional resistance between the yarn and the first, second and thirdneedles 14, 16, and 18, and yarn bending resistance at the points whereit bends at the first, second and third, needles 14, 16 and 18, andalso, if the moveable pulleys 8 and 9 are turned as described above,there is cross-over frictional resistance adjacent to the guide pulleys8 and 9. Since these various resistance are imposed successively on oneand the same yarn, their effects are accumulative, and add together topresent a single take up resistance at the th guide pulley ll. Tensionin the yarn as it passes through the 1st needle 14 is comparativelysmall, and variations in tension are liable to cause the yarn to jumpthe hook, and it is therefore preferable to provide the first needle 14with a further clip or blocking portion 19 which is applied after theneedle latch is closed.

There is formed in the front surface of the panel 2 a narrow, verticalguide groove 27. The guide groove 27 lies on a line at a positionbetween imaginary vertical lines passing through the fifth and sixthguide pulleys l1 and 12, and the top thereof is located at a point thatis below the line on which the pulleys 7, 8, 9,10, l 1 and 12 lie, andit extends to a point approximately level with the needle holders 13,and 17. At the top of the guide groove 27 there is fixed a support arm28a which extends perpendicularly from the front surface of the panel 2.The arm 28a supports a narrow, vertical guide rail 28 that is oppositeand parallel to the guide groove 27. One end, 21a, see FIG. 4, of aguide rod 21 is slidably inserted in the guide groove 27, and the otherend, 21b, is slidably inserted in the guide rail 28. The guide rod 21can either be straight or it can have the shape of a square-bottomed U.In the latter case, an attachment portion 24 is fixed to, or forms adownward extension from, the rod 21 near its end 21b (that is the outerend with respect to the panel 2). The attachment portion 24 curvesinwards (i.e., towards the panel 2) and its end 24a lies beneath thecenter of the middle portion 210 of the rod 21. To the attachementportion end 24a there is attached a downwardly looped, flexible chain23, the other end of which is attached to a fixable support rod 32(described later). The central portion 210 of the guide rod 21 passesthrough the bottom por tion of a stepped bracket-shaped attachmentportion 26, which is for attachment of weights 25 of varying values.Fixed to the upper portion of the step-shaped attachment portion 26there is a floating pulley 20, which is positioned with its hypotheticalturning axis parallel to the middle portion 210 of the guide rod 21. Theconfiguration of these various elements is such that the center of thefloating pulley 20, the center of the guide rod middle portion 21c, theweight 25, and'the attachment portion 24 end 24a all lie on thesame-vertical line. Alternatively, if the rod 21 is straight, it can bepassed through the floating pulley 20, along the axis thereof, and theattachment portions 24 and 26 formed integrally therewith.

Positioned on the opposite side of the panel 2 to the first guide,pulley 7 and at a pointbelow the level of the needle holders 13, 15 and17, there is a traverse rod 29, and positioned vertically below thetraverse rod 29 there is a take up reel 30, which possesses a cut-offnotch 30a, for cutting off yarn when the reel 31 is fully wound. Thetraverse rod 29 and take-up reel 30 are both driven by a motor 31 thatis located within the panel 2. The speed of the motor 31 can be adjustedto any desired value, for example, by a slide contact device for controlby changing impressed voltage, and the motor 31 can be caused to runconstantly at the speed selected. In other words, rotational speed ofthe takeup reel 30 can be controlled by the motor 31, and the speed ofthe reel 30 can be determined by means of a stroboscope, and anyadjustments made when required.

As described earlier, yarn is unwound from the cone 4, passed over thelead-in pulley 6, and then led, via the needles 14,16 and 18, andpulleys 7, 8, 9 and 10, to the fifth guide pulley 11. From the guidepulley 11 the yarn is led down, passed round and under the floatingpulley 20, led up to and passed over the sixth guide pulley12, led downand across to, and passed around the traverse rod.29, and thence leddown and-attached to the takeup reel 30. The floating pulley 20 is freeto ride up or down since the ends-2la and 21b of the guide rod can slidewithin the guide groove 27 and guide rail 28, and therefore the downwardforce applied to the floating pulley 20 must be such as to balance thetake-up resistance composed of the accumulated resistances from pulley 6through pulley -11. Put another way, if the downward force applied tothe floating pulley 20 is greater than the force of the accumulativetake-up resistance the floating pulley 20 will sink, and if it is less,the floating pulley 20 will rise. It is, of course, possible to setupper and lower limits to such up and down movement of the floatingpulley 20 by means of stops suitably located in the guide groove 27 andrail 28.

The tested yarn is traversed very slowly from the 6th guide pulley 12and wound on the take-up reel 30. The speed of travel of theyarndepends, of course, on the peripheral speed of the reel 30, which inturn depends on the rotational speed of 'the reel 30. In thisembodiment, fouryarn speeds are employed, the four speeds being 10, 25,50, and l0Om/min., it being also possible to-obtain other speeds ifrequired. The speed normally employed is that of 25m/min, whichapproximates the speed of needle operation in practical knittingmachines; the other speeds are selected for severe comparative testingof materials. For a given rotational speed of the reel 30, theperipheral speed, and hence the yarn speed, increases with the amount ofyarn wound on the reel 30, and therefore the yarn is cut by the cut-offnotch3la whenthe yarn wound thereon has reached a set amount.Alternatively, the speed at which yarn is led away from the testingequipment can be kept constant by taking the yarn out through a pair ofrollers and taking it up at some further stage.

The above-mentioned fixable support rod 32, to which one end of thechain 23 is attached, is slidably fitted in a vertical guide slot 33which is formed in the front of the panel 2 parallel to the guide groove27. The fixable support rod 32 passes through the slot 33 and hasattached to its other end inside the panel 2 a windup chain or similarmeans by which the location of the rod 32 in the slot 33 can bearbitrarily fixed. Such fixing means can be, for example, a chain 36which is at tached at one end to the inside end of the support rod 32and at the other end to a winch which is controlled by a wheel 34 at thefront of the base 1; turning the wheel 34 in one direction winds in thechain 36 and raises the support rod 32, and turning the wheel 34 in theopposite direction unwinds the chain 36 and allows the support rod 32 tobe lowered. The chain 23 is attached to and hangs freely between thefloating pulley attachment portion 24 and the support rod 32, and theamount of weight the chain 23 imposes on either the attachment 24 (andhence on the floating pulley 20) or the support rod 32 depends on thelength of chain between the lowest point of the chain 23 and theattachment portion end 24a or the outer end of the support rod 32. Theselengths can be varied as required by varying the height of the supportrod 32 in the guide slot 33 by the means described above; in otherwords, the weight imposed by the chain 23 on the support rod 32 or,acting through the connection portion 24, on the floating pulley 20 canbe varied as required. The weight of the chain 23 can be even over itslength, or if more convenient, its weight can be steadily increased overits length; in either case the principles described above are stillapplicable.

Beside the guide slot 35 there is a scale 33, which, for any position ofthe support rod 32, gives a reading of the total weight, including thatof the pulley 20 itself, imposed downwards on the floating pulley 20.This weight acting downwards on the floating pulley 20 varies with theheight of the support rod 32 and is countered by the force of theaccumulative take-up resistance at the 5th guide pulley 11, and theposition of the floating pulley 20 (which can move up and down with itsguide rod 21 guided in the groove 27 and rail 28) depends on thedifference between these upwardly and downwardly acting forces. In otherwords, by observing to what point (i.e., to what scale 35 reading) thesupport rod 32 must be moved to produce a downwardly acting weight tobring the floating pulley guide rod 21 to a set lower limit or stop, itis possible to determine the take-up tension of a yarn being tested.

The equipment described above can, of course, be provided with variousaccessories, such as an attached or mounted plumb-line and adjustablefeet on the base 1, to ensure that the panel 2 is vertical, or upper orlower display lamps that are actuated when the floating pulley 20reaches set upper or lower limits, or a warning buzzer for when thefloating pulley 2O exceeds set limits; also, for special testing it ispossible to pass yarn through or past a tensioner prior to feed in tothe equipment, or in cases where not enough tension to be detected isgenerated, a gauged tensioner can be interposed between the lead-inpulley 6 and 1st guide pulley 7; contrariwise, interchanging tensionersinterposed between the pulley 6 and pulley 7 provides a comparisioncheck of tensioners as well as of testing yarn quality. If a yarn beingtested breaks, the motor should be stopped to stop the yarn travel.Similarly, interchanging needles used for the same yarn gives acomparison check of needles as well as testing the yarn.

A cheese or cone of a yarn to be tested is placed on the stand 3, led upto the pulley 6 on the unwinding guide arm 5, where unwinding resistanceis produced, threaded onto the guide pulleys and through the needles toproduce friction, bending and needle resistance, and, where the moveablepulleys are turned around, cross-over resistance, passed under thefloating pulley on which is imposed a downwardly acting force to balancethe accumulative resistance force, and wound up by the take-up reel.Even if the speed of the take-up reel is constant, the position of thefloating pulley does not stay fixed, but varies due to the influence ofchanging resistances, particularly unwinding resistance. This variationof the position of the floating pulley is illustrated in FIG. 5(a),although there is variation it is generally evenly distributed above andbelow a set point, which is the position at which the force of theaccumulated resistance and the weight of the suspended chain balance;this is because, with the support rod 32 fixed in any particularposition the end of the chain 23 attached to the rod 32 is also fixed,while the other end attached to the attachment portion 24a is free tomove as the floating pulley 20 moves up or down, and if the accumulativeresistance force increases and raises the floating pulley 20, theattachment portion 24 end of the chain 23 is also raised and the lendthof the chain 23 on the floating pulley 20 side, and hence the weightimposed by the chain 23 on the floating pulley 20, is automaticallyincreased, and similarly, there is an automatic decrease in the weightimposed by the chain 23 on the pulley 20 when the accumulativeresistance force decreases and allows the floating pulley 20 to movedown.

For any particular yarn, therefore the floating pulley 20 has a pointthat represents a point of stability, and so one method of determiningthe total take-up tension of a yarn is to adjust the position of thesupport rod 32 so that the point of stability of the pulley 20 is stablysettled at an intermediate point of the groove 27 and the rail 28, andthen take a reading of the position of the support rod 32 from the scale35 indicating the weight imposed on the pulley 20, that is the force ofthe accumulative take-up tension. When this reading is taken it can becompared with set values, for assessing the yarn as good, medium orpoor. Therefore, a method of assessing yarn quality is to observe the upand down movement of the pulley 20 and note the approximate center pointof this up and down movement; adjust the position of the support rod 32until the center point of the up and down movement of the pulley 20 issettled at a certain predetermined position; and then take a reading ofthe position of the support rod 32 from the scale 35. In this method thescale is calibrated with weights imposed on the pulley 20 at everyposition of the support rod 32 while the pulley 20 is settled at acertain predetermined position. Another method of determining the totalaccumulative take-up tension of a yarn is to note at what sale 35reading the support rod 32 must be placed for the support arm 21 of thefloating pulley to settle at a bottom stop. It should be noted here thatthe amount the pulley 20 moves up and down varies in a cycle, and thebottom stop selected should be level with the highest one of the bottompoints of the downward movement; the movement of the pulley 20 isindicated by the heavy line in FIG 5(b). In this method the scale iscalibrated with weights imposed on the pulley 20 at every position ofthe support rod 32 while the pulley 20 is settled at the bottom stop. Itwas found experimentally that if the amplitude of the up and downmovement of the pulley 20 is less than 5 cm, that the same assessment ofyarn quality is obtained if a weight 25 is used alone, without using thechain 23; the quality of the yarn being tested can be assessed by usinga set weight W, as shown in FIG. 6.

Thus, a yarn is unwound and passed through portions where friction andbending are caused, and then brought to point where the variousresistances act accumulatively, and by determining the weightimposed ona chain, and comparing the value to standard values it is possibleto'determine the total take-up resistance of the yarn. The resistancethus measured is a sum total of friction between parts of the yarn,friction between the yarn and needles, and bending resistance, andtherefore represents a value that gives a direct assessment of thequalities of the yarn foruse in a practical knitting machine.

Amethod for suchcomparison is to'previously determine classes of yarnquality, such as good, medium, and poor, based on factors such asexcellent articleratio, occurrence of breaks or flaws, etc., asencountered in actual industrial operations; then determine a standardvalue for making an assessment of yarn quality asmentioned hereinafter,by means of measuring yarnsas to which results in practical knitting arealready known, by the device of the present invention, without using thechain 23, but by only setting the pulley 20. It is necessary to find outthe amount of weight 25 to satisfy the conditions that the pulley issettled onthe bottom stop by observing a good quality yarn, is moving upand down between the upper and bottom stops by observing a mediumquality yarn, and rises to settle under the upper stop by observing apoor quality yarn. Accordingly, this makes it possible to obtain anassessment of yarn quality by means of comparing the standard value withthe amount of tension measured withrespect to yarns of various kinds. Itis of course necessary to previously determine a number of differentstandards to correspond to different knitting conditions and differenttypes of yarn. v

With the device of the invention when observing without using the chain23 but only the setting pulley 20, it is not only possible to classifyyarn tested into the three qualities good, medium, or poor, but alsopossible to make finer assessments, since the floating pulley 20 risigfrom the bottom stop sometimes indicates that yarn quality is gettingsomewhat worse than a good quality yarn, and the floating pulley 20moving down from the upper stop sometimes indicates that yarn quality isgetting somewhat better than a poor quality yarn.

With the present device it is also possible, by crossing yarn overitself after it has passed throughthe needles, to produce cross-overresistance adjacent to the needles. This increases contact of the yarnwith the needles, and therefore increased tension is produced closer tothe movable pulleys, and this extra tension caused by the needles iseffective for detecting, for example, yarn unevenness.

Also, in cases where there are problems of too much tension beinggenerated, it is possible to eliminate crossover resistance by simplynot turning the moveable pulleys; in this case the accumulatedresistance consists of abrasion between yarn and needles, bendingmoment, and unwinding resistance, and is still applicable to industrialpractice.

The invention therefore provides a device for determining yarn qualityon the basis of bending moment and various friction or otherresistances, and the invention eliminates the necessity formaking'separate tests, but makes it possible to obtainan assessment thatis the equivalent of many tests in a simple rapidprocess.

An explanation of a second embodiment of the invention .is'given belowwith reference to FIG. .6.

In the-equipment of the-secondembodiment pulleys '7, 8, 9 and '10, aremounted evenlyspaced on the front of the upper portion-of a verticalpanel section P and ina straight line that is belowand parallel to theline of the pulleys 7, 8, 9 and '10, there are mounted three needleholders I13, '15 and 17, which are of conventional design .to permiteasyinterchanging of needles 14, '16 and 18 of various gages; the needleholder 13 lies between pulleys 7 and 8, the holder 15 lies betweenpulleys 8 and 9, and the holder 17 lies between pulleys 9 and '10.Nextto and aligned with the panel section P thereis a small verticalpanel section O which is'the same height as the panel section P butnarrower, being about one quarter of the width of the latter width. Nearthetop of-the panel section Q are mounted two pulleys 11 and -12 on aline that is parallel to the top of the panel section Q (and also ofpanel P) Below and between the pulleys 11, l2-there is provideda'floating pulley 20. Nextto the panel section 0 by the side furtheraway from the panel section-P, there is placed a take-up unit 30 whichis for winding 'in yarn at a constant speed. Adjacenttothe lead+in sideof the panel section P, that-is the pulley 7 side and opposite to thepanel section Q side, there is provided a stand 3, and above the stand 3and on approximately the same level as the pulleys 7,8,9 and 10 there isprovided a pulley '6 which-is designed for'minimum rotational friction,usingany conventional means such as bearings,'Snell wire, etc., andwhich is a guide for controlling the unwinding of yarn. Between thepulley 6 and the pulley 7 there is provided a yarn tensioner 41 for usewhen required.

A cone or cheese 4 of a yarn A to be tested is placed on the stand 3 andthe yarn A is unwound,,led upwards, passed over the pulley'6, throughthe tensioner 41, over pulley 7, through needle 14, over pulley 8,through needle 16, over pulley 9, through needle 18, over pulley 10,over pulley ll, underthe floating pulley 20, over pulley l2, andthen leddown and attached to the takevup unit 30.

In the section P the pulleys 8 and 9 can be optionally turned, so as togenerate yarn cross-over friction. The path of the yarn A through thevarious parts of the section P is subject to various resistances andforces, which include frictional resistance, bending, needle to yarnresistance, and, if the yarn A is crossed on itself,

cross-over resistance; these resistances are additive and when the yarnA comes to the section Q are combined to represent a single tensileforce. The purpose of the section Q is to determine the value of thissingle tensile force, and this is achieved by hanging a weight W of astandard value on the floating pulley 20, and

.then observing to what position the floating pulley 20 ,moves. Toassist thisobservation there are provided two stops, or stop marks,42and 43, on the front of the section 0 and on the path of the .up anddown move- .ment of the floating pulley 20. The stop 42 is a lower stopmark, the stop 43 is an upper stop mark. If the force of the yarntension is greater than half the sum of the weight of the pulley '20 andof the standard weight W, the floating pulley 20 rises to the upper stop43; if

the tensile force is smaller than the above-mentioned value, the pulley20 moves down to the lower stop 42; and if the tensile force and thedownward force of the combined weight of the pulley 20 and weight W areapproximately equal, the pulley 20 moves between the upper and lowerstops 43 and 42. The value of the weight W is determined in reference tostandard yarns; that is, yarns of a previously determined quality arerun through the sections P and Q and it is then observed what weight Wbrings the pulley 20 to what positions, in order to determine standardreference stop positions and values of the weight W. Thereafter, toassess quality of a yarn on the basis of bending, needle to yarn, andcross-over frictional resistance, it is merely necessary to observe towhat position the floating pulley 20 moves with a weight W attached, andthe yarn can be immediately classed as poor, medium, or good.

An alternative method of passing a yarn through the section P is, asillustrated in FIG. 7, not to turn the pulleys 8 and 9 but to cross theyarn over itself at the points where it is passed through the needles,this method (shown in FIG. 70) being useful for detection of yarnunevenness; or in cases where there is a problem of too much resistance,the yarn can be passed through the section P without being crossed overitself at any point (as shown in FIG. 7b). In the section Q the tensileforce can of course be mesured directly by means of a spring balance Winstead of the weight W, as illustrated in FIG. 8. In this case, theresistance accumulated on the yarn which acts as taking-up tension ofthe yarn is measured directly by the spring balance W.

Classification of yarns, etc., by the equipment of the present inventionand by the actual knitting processes correspond exactly, as is shown inthe Comparison Table l. The materials tested were 100 percent cottonyarn, cotton and acryl blends of different count, numbers, andmercerised yarn; also test materials which had the same count number butwhich had had different treatment (mercerising, softening), were used.The items marked A are unmercerised thread, and the items marked AA arethe same items subsequently waxed.

Two methods of assessing the quality of a material are, as describedearlier, to use a weight only and not the chain 23, in which case a yarncan be classed as good, medium or poor, or to use the chain 23 attachedto the floating pulley in which case yarn quality can be assessed over acontinuous range as well as into the same three classes, good, medium,and poor.

In the second method, since assessment is continuous, it is possible toassess quality by a quantified scale.

The yarn take-up speed in both methods was 50 m/min., and the resultsobtained are shown in Table l where they are compared with resultsobtained by actual knitting machine operation. It is seen that there isan extremely close match between the sets of results. Thusclassification of yarn and similar materials is the same as thatobtained in actual industrial processes, but

the invention produces this same classification without the necessity ofcarrying out a series of separate tests, but in one simple, quicklycompleted operation which does not require skilled workmen. Theinvention thus speeds and simplifies yarn classification and istherefore of great advantage in industry.

Although the present invention has been fully de-.

scribed with reference to the accompanying drawings in connection withthe preferred embodiments thereof,

various changes and modifications will be apparent to those skilled inthe art. Therefore, the present invention is not to be limited therebyand such changes and modifications should be construed as includedwithin the scope of the present invention unless otherwise they departtherefrom.

TABLEI w Cross-over Abrasion Friction Between Yarn yp Force and KnittingNeedle Bending 0f Unwinding Between Moment No. mp Resist- Yarn andFriction Gauge of X 10- Yarns ance (g.) Ymlgi Force (g.) KnittingNeedles (gem) 1A Cotton 0.38 11.7 31.5 18 1.31 2AA & Mercerized 0.35 9.524.0 18 1.31 3 Yarn 30/2 0.30 9.2 22.8 18 1.30 4 0.38 9.7 20.9 18 1.74 50.47 *18.1 *49.3 18 *4.19 6 0.44 *15.2 *42.5 18 *2.20 7 *0.98 11.2 *41.518 *2.27 g

8A 100% Cotton & 0.32 10.7 26.5 18 0.97 9AA Mercerized 0.30 8.9 22.8 180.97 10 Yarn 40/2 0.35 9.1 18.4 18 1.20 11 0.25 9.7 22.7 18 1.14 12 0.4011.7 *27.1 18 *l.80

13A 100% Cotton 0.25 10.2 25.8 26 0.78 14 & Mercerized 0.28 8.7 19.6 260.83 15 Yarn 56/2 0.25 10.0 *24.8 26 0.85 16 0.24 7.7 20.8 26 0.89

17A Blended Yarn 0.30 11.7 23.4 18 1.16 18 of Cotton & 0.33 9.7 20.3 181.13 Acrylic 32/2 0.44 14.5 *29.7 18 1.19

20 Blended Yarn 0.31 9.0 16.5 18 0.97 21 of Cotton 8L 0.26 8.3 17.9 180.93 22 Acrylic 32/42 0.39 10.2 *26.4 18 0.94

TABLE 1Continued Tensile Tensile Initial Yarn Valuation Valuation Nostrength elongation youngs unevenness according by the (g) modulus toactual invention (g/ knitting 1A 827 6.4 40.6 8.5 Acceptable Acceptable2AA 827 6.4 40.6 Excellent Excellent 3 833 4.8 63.0 8.6 ExcellentExcellent 4 902 4.6 67.2 8.4 Acceptable Acceptable 5 l 141 6.2 61.0 8.2Not acceptable *Not acceptable 6 1043 4.0 87.l 8.6 Not acceptable *Notacceptable 7 977 5.1 63.6 9.0 Not acceptable *Not acceptable 8A 589 6.339.9 8.6 Acceptable Acceptable 9AA 589 6.3 39.9 Excellent Excellent 10'604 4.4 64.4 9.] Excellent Excellent 1 1 773 5.5 64.4 8.5 AcceptableAcceptable 12 586 5.7 45.9 9.5 Not acceptable *Not acceptable 13A 3995.3 45.6 10.9 Acceptable Acceptable 14 424 4.0 67.9 1 1.5 AcceptableAcceptable 15 548 4.6 70.2 10.8 Not acceptable *Not acceptable 16 4444.0 66.0 10.6 Excellent Excellent 17A 432 8.8 23.7 9.6 AcceptableAcceptable 18 423 5.7 31.2 9.2 Acceptable Excellent 19 414 5.7 30.1 9.1Not acceptable *Not acceptable 20 428 6.1 32.4 8.5 Excellent Excellent21 404 5.7 31.8 9.2 Excellent Excellent 22 399 4.9 36.5 9.1 Notacceptable Not acceptable TABLE 2 mulated resistance on the yarn isdetected by detecting the position of the free end of a chain when theother Yarn Gauge number d end of the chain is suspended from the yarnwhich has number of knitting Loa ttl d in a fix d osition K' d of amcount needle Se 6 e p m y 4. A method according to claim 1, wherein theaccu- 1 3 & 30/2 18 mulated resistance on the yarn is detected bydetecting m the position of a floating pulley around which the yarn do.40/2 18 60 is run and to which. is connected one end of a chain the 56/226 4O other end of which 18 kept ata fixed position.

5. An apparatus for assessing. the knitting quality of Blended Yam 9yarn comprising a means for leading yarn from a cheese 32/2 80 or coneor similar device in an unwinding direction, Cotton & Acyrlic means forwinding in said yarn at a constant speed, a 32/42 18 60 40 means betweensaid leading means and said winding What is claimed is:

l. A method for assessing the knitting quality of yarn and similarmaterials comprising placing a cone or similar mass of yarn the qualityof which is to be assessed in a fixed position, passing said yarn in anunwinding direction from said cone and successively through a means forimposing resistances on said yarn including yarn to yarn frictionalresistance, yarn to needle frictional resistance, and bendingresistance, and then winding said yarn up at a constant speed by a takeup means for unwinding the yarn from the cone for imposing an unwindingresistance thereon and imposing yarn to yarn frictional resistance, yarnto needle frictional resistance and bending resistance on said yarn, anddetecting at a point between the last of said resistance means and takeup means the yarn tensile force representing the accumulative value ofsaid resistance imposed on said yarn, and comparing the detected valuewith previously detemiined standard values.

2. A method according to claim 1, wherein the accumulated resistances onthe yarn is detected by placing a weight on said yarn and comparing themovement of said weight between predetermined limits due to yarn tensileforce with the similar movement of said weight for a good quality yarn.

3. A method according to claim 1, wherein the accumeans for generatingresistances to be imposed on said yarn including yarn to yarnfrictional-resistance, needle to yarn frictional resistance and bendingresistance in a yarn passed therethrough, a detecting means between saidresistance generating means and said winding means for detecting a yarntensile force representing the accumulative value of said resistancesincluding unwinding resistance imposed on said yarn, and a meansoperatively associated with said detecting means for measuring saidaccumulative tensile force detected by said detecting means incomparison with a previously determined standard value.

6. An apparatus according to claim 5, wherein said detectingmeanscomprises a floating pulley which is suspended on said yarn onwhich said accumulative tensile acts upwards, and said measuring meanscomprises a weight attached to said floating pulley so as to urge itdownwardly and vertically spaced limit'means' between which said weightmoves.

7. An apparatus according to claim 5, wherein said detecting meanscomprises a floating pulley which is suspended on the yarn to detectsaid accumulative tensile force.

8. An apparatus according to claim 5, wherein said. detecting meanscomprises a floating pulley which is; suspended on said yarn on whichsaid accumulative tensile force acts upwards, and said measuring means9. An apparatus according to claim 5, wherein said generating meansincludes at least one pulley for guiding the yarn and at least oneneedle held by a holder through which the yarn is passed, both saidpulley and needle being respectively fixed at certain positions.

1. A method for assessing the knitting quality of yarn and similarmaterials comprising placing a cone or similar mass of yarn the qualityof which is to be assessed in a fixed position, passing said yarn in anunwinding direction from said cone and successively through a means forimposing resistances on said yarn including yarn to yarn frictionalresistance, yarn to needle frictional resistance, and bendingresistance, and then winding said yarn up at a constant speed by a takeup means for unwinding the yarn from the cone for imposing an unwindingresistance thereon and imposing yarn to yarn frictional resistance, yarnto needle frictional resistance and bending resistance on said yarn, anddetecting at a point between the last of said resistance means and takeup means the yarn tensile force representing the accumulative value ofsaid resistance imposed on said yarn, and comparing the detected valuewith previously determined standard values.
 2. A method according toclaim 1, wherein the accumulated resistances on the yarn is detected byplacing a weight on said yarn and comparing the movement of said weightbetween predetermined limits due to yarn tensile force with the similarmovement of said weight for a good quality yarn.
 3. A method accordingto claim 1, wherein the accumulated resistance on the yarn is detectedby detecting the position of the free end of a chain when the other endof the chain is suspended from the yarn which has settled in a fixedposition.
 4. A method according to claim 1, wherein the accumulatedresistance on the yarn is detected by detecting the position of afloating pulley around which the yarn is run and to which is connectedone end of a chain the other end of which is kept at a fixed position.5. An apparatus for assessing the knitting quality of yarn comprising ameans for leading yarn from a cheese or cone or similar device in anunwinding direction, means for winding in said yarn at a constant speed,a means between said leading means and said winding means for generatingresistances to be imposed on said yarn including yarn to yarn frictionalresistance, needle to yarn frictional resistance and bending resistancein a yarn passed therethrough, a detecting means between said resistancegenerating means and said winding means for detecting a yarn tensileforce representing the accumulative value of said resistances includingunwinding resistance imposed on said yarn, and a means operativelyassociated with said detecting means for measuring said accumulativetensile force detected by said detecting means in comparison with apreviously determined standard value.
 6. An apparatus according to claim5, wherein said detecting means comprises a floating pulley which issuspended on said yarn on which said accumulative tensile acts upwards,and said measuring means comprises a weight attached to said floatingpulley so as to urge it downwardly and vertically spaced limit meansbetween which said weight moves.
 7. An apparatus according to claim 5,wherein said detecting means comprises a floating pulley which issuspended on the yarn to detect said accumulative tensile force.
 8. Anapparatus according to claim 5, wherein said detecting means comprises afloating pulley which is suspended on said yarn on which saidaccumulative tensile force acts upwards, and said measuring meanscomprises a freely suspended chain, one end of which is attachEd to saidpulley, and a means that can be moved and fixed and to which the otherend of said chain is attached so as to vary the fraction of the weightof said chain imposed downwardly on said floating pulley.
 9. Anapparatus according to claim 5, wherein said generating means includesat least one pulley for guiding the yarn and at least one needle held bya holder through which the yarn is passed, both said pulley and needlebeing respectively fixed at certain positions.